Infarction is defined as an area of necrosis due to decreased blood flow. It can be hemorrhagic or anemic, red or white. Cardiac biomarkers such as troponin T and I, creatine kinase (CK-MB), and myoglobin are released from damaged heart muscle and can help evaluate myocardial injury. These biomarkers have characteristic rise and fall patterns. Renal failure can alter the diagnostic accuracy of cardiac biomarkers. Treatment of acute myocardial infarction focuses on restoring normal blood flow and salvaging heart muscle.

2. INFARCTION
BY
DR ABDUL AZIZ SHAIKH

3. INFARCTION
• Defined as an area of
necrosis* secondary to
decreased blood flow
• HEMORRHAGIC vs. ANEMIC
• RED vs. WHITE

4. WEDGE SHAPED SCARRED INFARCT
FIBROSIS implies that it is old (months to
years)

5. Microscopic features

6. This is an acute renal infarction. Note the
wedge shape of this zone of coagulative
necrosis resulting from loss of blood supply
with resultant tissue ischemia that produces
the pale infarct.

7. splenic infarcts

8. Hemorrhagic infarction

9. Cardiac Biomarkers
• Cardiac biomarkers are protein
molecules released into the blood
stream from damaged heart muscle
• Since ECG can be inconclusive ,
biomarkers are frequently used to
evaluate for myocardial injury
• These biomarkers have a
characteristic rise and fall pattern

10. Troponin T and I
• These isoforms are very
specific for cardiac injury
• Preferred markers for detecting
myocardial cell injury
• Rise 2-6 hours after injury
Peak in 12-16 hours
Stay elevated for 5-14 days

11. Creatinine Kinase ( CK-
MB)
• Creatinine Kinase is found in heart
muscle (MB), skeletal muscle (MM),
and brain (BB)
• Increased in over 90% of myocardial
infraction
• However, it can be increased in
muscle trauma, physical exertion,
post-op, convulsions, and other
conditions

12. Creatine Kinase (MB)
• Time sequence after myocardial
infarction
Begins to rise 4-6 hours
Peaks 24 hours
returns to normal in 2 days
• MB2 released from heart muscle and
converted to MB1.
• A level of MB2 > or = 1 and a ratio of
MB2/MB1 > 1.5 indicates myocardial
injury

13. Myoglobin
• Damage to skeletal or cardiac
muscle release myoglobin into
circulation
• Time sequence after infarction
Rises fast 2hours
Peaks at 6-8 hours
Returns to normal in 20-36 hours
• Have false positives with skeletal
muscle injury and renal failure

14. Renal Failure and Renal
Transplantation
• Diagnostic accuracy of serum
markers of cardiac injury are
altered in patients with renal
failure
• Cardiac troponins decreased
diagnostic sensitivity and
specificity in patients receiving
renal replacement therapy

15. CBC
• CBC is indicated if anemia is
suspected as precipitant
• Leukocytosis may be observed
within several hours after
myocardial injury and returns
returns to levels within the
reference range within one week

16. Chemistry Profile
• Potassium and magnesium levels
should be monitored and corrected
• Creatinine levels must be considered
before using contrast dye for
coronary angiography and
percutanous revascularization

17. C-reactive Protein (CRP)
• C- reactive protein is a marker
of acute inflammation
• Patients without evidence of
myocardial necrosis but with
elevated CRP are at increased
risk of an event

18. Chest X-Ray
• Chest radiography also reveals
complications of myocardial
infarction such as heart failure
• Echocardiography
• Echocardiography

19. • Therapy
•The goals of therapy in
AMI are the expedient
restoration of normal
coronary flow and the
maximum salvage of
functional myocardium